In pumps of this kind there is a problem of controlling the vanes so that they are at all times properly oriented as they travel around the annular passageway in the housing. The construction of the above-mentioned patent and other constructions proposed by the inventor disclose different possibilities for carrying out the control of the vanes in pumps of this kind by means of cam tracks. The control of the vanes adjacent the sealing portion of the passageway presents the most difficult problem in such pumps particularly with regard to providing a practical and commercial pump which is suitable for special applications. The applicant has proposed arranging spring elements between two cam tracks which are movable wholely by themselves and with the help of additional rollers support the cam rollers. This arrangement is favorable with respect to energy requirements and is highly suitable for many applications. However when higher speeds are required the speed of the rollers of the spring elements of a suitable small size can reach unacceptable values for example 5,000 to 6,000 rpm with a rotor speed of about 1,000 rpm. Also the constantly moving spring elements can lead to unacceptable vibrations. On the whole spring pressed parts with a second guiding flank lead to the danger that all the vanes may be turned when it is desired to turn only one because of coarse substance in the pump between the vanes and the wall of the passageway.